Texture and microstructure imaging in six dimensions with high-energy synchrotron radiation

The texture of a material can be calculated from several pole figures, which, in turn, are usually measured by one of several 'step-scan' techniques. In these techniques, the finite step width limits the attainable orientation resolving power. In the present paper, the discontinuous step-scan technique is replaced by a continuous 'sweeping' technique based on the continuous movement of an area detector during exposure. In this way, continuous two-dimensional 'images' of pole figures are obtained, without the necessity of interpolation. Similar sweeping techniques are also being used to obtain continuous images of other sections and projections of the six-dimensional 'orientation - location' space which characterizes a polycrystalline structure completely. The high potential orientation and/or location resolving power of these imaging techniques can only be reached with synchrotron radiation. In the present paper, the measurements were made at the high-energy (short-wavelength) beamline BW5 at HASYLAB/DESY in Hamburg. The high orientation and location resolving power implies the necessity to distinguish 'grain-resolved' textures and microstructures ( mainly in recrystallized materials) from 'continuous' ones ( mainly in deformed materials). Under certain conditions, it is thus possible to obtain the complete six-dimensional 'orientation stereology' of grain-resolved microstructures. The new methods are illustrated with several examples, including technological applications.